This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A342854 #31 Feb 16 2025 08:34:01 %S A342854 0,0,0,0,1,2,5,9,17,26,41,60,88,120,163,213 %N A342854 Maximal number of 2413 patterns in a permutation of 1,2,...,n. %C A342854 Equivalently the maximal number of 3142 patterns in a permutation of 1,2,...,n. %H A342854 M. H. Albert, M. D. Atkinson, C. C.Handley, D. A. Holton, and W. Stromquist, <a href="https://doi.org/10.37236/1622">On packing densities of permutations</a>, The Electronic Journal of Combinatorics, 9(1) (2002). %H A342854 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PermutationPattern.html">Permutation Pattern</a> %e A342854 For n = 6, the permutation 246135 has a(6) = 5 subsequences with the same relative order as 2413: 2413, 2613, 2615, 4615, and 4635. %e A342854 All other permutations in S_6 have 5 or fewer such subsequences. %Y A342854 Analogous for other patterns: A000292 (123), A000332 (1234), A061061 (132), A100354 (1432), A342646 (4213), A342853 (1324). %Y A342854 Cf. A342860. %K A342854 nonn,more %O A342854 0,6 %A A342854 _Peter Kagey_, Mar 25 2021 %E A342854 a(11)-a(14) from _Hugo Pfoertner_, Mar 26 2021 %E A342854 a(15) from _Hugo Pfoertner_, Apr 05 2021